Existing compensation structures for Electric Power Steering (EPS) systems often use torque loop compensation for an electric motor control system. In such existing EPS systems, a torque compensator, commonly a notch filter, is employed in the torque path to provide phase lead to ensure that the system remains stable. However, application of a torque compensator may make the EPS system sensitive to disturbances that include frequency content near the notch frequency. The compensator may also cause the on-center feel (torque gradient) to feel less precise.
While well suited for its intended purposes, the torque compensator may not provide desired characteristics under all operating conditions. For example, such a system may not provide desired characteristics under all vehicle speed conditions. With the aforementioned considerations, it may be difficult to apply torque compensation in some vehicles and tune the control system to achieve acceptable performance. Therefore, what is needed is a method for modifying the compensation utilized as a function of vehicle operating parameters.